Pigment composition and method of manufacture



the free air that separates the pigment particles.

3,014,810 Patented Dec. 26, 1961 ice 3,014,810 PIGMENT CGIt tPOSETIQNAND METHOD OF MANUFACTURE Jack N. Dybalski and Donald J. Berenschot,Chicago, and Werner L. Riegler, Western Springs, 111., assignors, bymesne assignments, to Armour & (Zompany of Delaware, Chicago, 111., acorporation of Delaware No Drawing. Filed Sept. 8, 1958, Ser. No.759,418 18 Claims. (Cl. 106-408) This invention relates to an improvedpigment composition. In one of its aspects, this invention relates to amethod for preparing a water-wet pigment for incorporation into an oilsystem. In another of its aspects this invention relates to thepreparation in situ of pigments.

Pigments are finely divided insoluble solids which are used in manymaterials such as coating compositions, rubber, etc., for many differentpurposes. In coating compositions they are mostly used to provide acolor or hue, but they also function as opacifiers. In rubber,especially tire rubber, carbon black is used to impart strength andabrasion resistance as well as color. It is hardly possible to lookaround and not see some article which contains a pigment of one sort oranother.

In practically every application of pigmentary materials it is necessarythat they be dispersed, generally in the liquid medium. Pigmentdispersion, as it is encountered in the field of coating compositions,involves generally transferring a dry pigmentary material existingreally as a heterogeneous dispersion in air or water to a dispersion ina liquid such as an oil as uniformly as possible. The attainment ofoptimum dispersion usually results in the maximum practical developmentof such desirable properties as tinctorial strength, opacity, gloss anduniform pigment particle distribution.

Pigment particles can be pictured as irregularly shaped solidssurrounded by a bound envelope of air, gas or moisture which is to beconsidered distinctly different in its physical relationship to thepigment as compared with Both the free air and the surface-bound airconstitute the initial obstacle to be overcome in converting the pigmentfrom the dispersion in the air to a dispersion in the liquid. Pigmentsin the dry form are generally in the form of agglomerates which may beeither in a relatively loose or a compacted condition. In the dispersionprocess, a

vehicle is added to the pigment mass in a mixing opera-' tion which isextended further by a so-called grinding operation. The dispersionprocesses employed by the manufacturer of coating compositions are notreally true grinding operations. They do not reduce the primary particlesize of the pigment as originally manufactured, but are intended toapproach the primary particle size of the pigment. The tendency of thepigment to cluster or coalesce under the conditions of packing,shipment, and storage, as well as a natural tendency of many pigments toagglomerate when initial wetting is attempted, are factors which leadone to believe that if reduction to primary particle size occurs, itoccurs in the dispersion process. Any attempt to truly grind thepigment, it actually accomplished, would probably result in millscoring, contamination by abrasion, change in color, quality,

etc.

. As a result of the work done on a mixture of pigment and vehicle, apigmented composition is obtained which may be represented by twoextreme conditions, with, of

course, the possibility of an actual composition which combines thecharacteristics of both. A poor dispersion is one in which the work donehas failed to separate the pigment particles with the result that muchof the original air is retained and the particles have become tightlypacked into a hard aggregate as a consequence of the forces exerted. Theideal result is one in which the pigment particles have been completelyseparated with an envelope of adsorbed vehicle replacing the originalair envelope, and free vehicle displacing the original free air.

Wetting agents are well known in the field of dispersion, and areemployed in emulsification as well 'as in dispersing solids. Since mostpigment manufacturing processes involve the formation of the pigment atsome stage as a precipitate in an aqueous system, it is known to coatthe pigment with a wetting agent to render the pigment surface more oilacceptable. However, most of I the pigment wetting agents on the markettoday are potassium or sodium rosinates and petroleum sulfonates, whichrely solely on the partial adsorption of the reagent upon the pigment inwater, and are only 50% efficient. These types of compounds generallyremain water-soluble, and a large portion is washed away in the filtratewhen filtering the pigment.

We have discovered that if an aqueous precipitate of pigmentarymaterials is treated in such a manner as to ultimately coat the pigmentparticle with a special type of mixture of cationic surface-activechemicals, which will be described with particularity hereinafter, thecoating will remain on the pigment during the filtrationstep and willact as a spacer between the pigment particle and prevent the formationof clusters of pigment particles or agglomerates. We have alsodiscovered that our special mixture of cationic surface-active chemicalswill materially enhance dispersion and prevent pigment agglomerationwhen incorporated directly into oil systems (in situ) prior to theaddition of dry, uncoated pigment. Further, the pigment particles can beground to a finer grind number with fewer passes through theconventional mill than is otherwise required. Also, we have discoveredthat the pigments coated with our unique mixture are much easier todisperse into plastics and rubber and result in finished products havingimproved physical properties such as tensile strength, modulus,elongation, hardness, etc. It has also been discovered that rubbercontaining pigments coated in accordance with our invention exhibitenhanced sunlight aging characteristics as well as some other chemicaland physical properties normally associated with rubber and plastics.

It is therefore an object of the present invention to provide animproved pigment composition.

It is a further object of this invention to provide a method forpreparing water-wet pigments for incorporation into oil systems.

It is still another object of this invention to provide an improved insitu method for preventing pigment agglomerates.

Further additional objects of this invention will become apparent fromthe following description:

In one of its aspects, the present invention is applicable tohydrophilic or water-Wettable pigments and preferably to about 5% byweight of a mixture containing from 0.25 to 10 parts by weight based onthe weight of the pigment of a quaternary ammonium compound having theformula per part of a tertiary aliphatic amine having the formulawherein in each of the foregoing formulae R is an aliphatic hydrocarbonradical having from 8 to 22 carbon atoms, R is a lower alkyl radicalhaving from l to 3 carbon atoms, X is a halogen such as chlorine orbromine and x and y are integers of one or more having a sum not greaterthan 10. in a preferred embodiment of our invention an aqueous slurry ofthe selected pigment is admixed with from about 0.2 to about 5% byweight of pigment of a mixture containing from 5 to parts by weight ofthe quaternary ammonium compound described above per part of awater-soluble salt of the tertiary amine described above, such as theacetate or hydrochloride, and agitated for a time suflicient for themixture to become coated on the pigment particle, usually about 10 tominutes. Next a stoichiometric quantity, or slight excess, of a diluteaqueous solution of a base such as sodium hydroxide or potassiumhydroxide required to convert the acetate or hydrochloride salt back tothe tertiary amine base in added and the agitation continued until thepig ment is uniformly coated with the mixture of quaternary ammoniumcompound and tertiary amine, and the alkali metal acetate or chloridereaction product is dissolved in the aqueous phase. The coated pigmentcan then be collected in a filter and dried in an oven at about 60 to 70C. while the clear filtrate containing the dissolved salt is discarded.The coated pigment is then ready for incorporation into an oil oroleoresinous vehicle and will disperse with far less effort than anuncoated pigment. If the selected pigment is one intended forincorporation into rubber, as coated in accordance with this preferredaspect of the present invention it can be completely dispersed thereinwith considerably less effort than if it were not coated or if it werecoated with conventional materials.

As describedhereinabove, the coating composition for pigments of thepresent invention consists of a mixture of from 0.25 to 10 parts byweight, preferably from 5 to 10 parts by weight, of a quaternaryammonium compound having theformula per part of a tertiary aliphaticamine having the formula ro BzCHgOhH \orncmonn wherein in each of theforegoing formulae R is an aliphatic hydrocarbon radical having from 8to 22 carbon atoms, R is a lower alkyl radical having from 1 to 3 carbonatoms, X is a halogen such as chlorine or bromine, and x and y areintegers of one or more and having a sum no greater than 10. Thesecompounds can be applied to the pigment either individually or inadmixture, although it is preferred to apply them in admixture. Whenthey are ever, that when the pigments to be coated are in anaqueoussystem, a Water-soluble salt of the tertiary ali-' phatic amine, such asthe acetate or hydrochloride, is first employed followed by conversionwith a base such as sodium hydroxide or potassium hydroxide.

In another of its aspects, this invention contemplates in situ coatingof pigments. This method involves the direct addition oftheabove-described special cationic surface-- active chemical combinationinto organophilic media suchas oil systems, oleoresinous materials,rubber, and plas-' tics. This novel technique of pro-treating theorganophilic' substance permits either a dry pigment addition or directflushing of a water-wet pigment cake, and can be em-- ployed to attainexcellent dispersion, fineness of grind and extended shelf-life withlittle or no segregation or separation.

The quantity of the mixture coated upon the pigment in accordance withthe practices of this invention will vary between about 0.05 and 5Weight percent based on the weight of dry pigment, although the end useof the pigment will have a relation to the quantity employed. Forexample, when the pigment is to be used in coating com-' positions, itis preferred to employ approximately from: 0.5 to 5 weight percent ofcoating on the pigment particle, When the pigment is to be incorporatedinto a rubber or plastic composition, it is preferred to employ fromabout 0.2 to about 1% by weight of coating. With respect to the latterend use of the pigment, higher quantities of the coating materialusually have an adverse effect upon the properties of the finishedrubber or plastic composition. With respect to the use of the coatedpigments for incor-- poration into coating compositions, higherquantities than 5% by Weight can be employed although there is nobeneficial efiect gained from such higher quantities.

We have discovered that with regard to the quaternary ammonium compoundsemployed in the described mixture, it is necessary that the compoundhave two long chain aliphatic hydrocarbon groups rather than only one.When the quaternary ammonium compound employed has only one aliphatichydrocarbon group the pigment is not effectively coated to convert itcompletely from a hydrophilic to a hydrophobic particle. Further, wehave found that when the quaternary ammonium compound is employed' byitself rather than in combination with the tertiary aliphatic amine, thecoating process is much less effective. it is also important inachieving the beneficial results of the present invention that thetertiary aliphatic amine contains not more than 10 moles of condensedethylene oxide. If more than this quantity of ethylene oxide is presentthe tertiary aliphatic amine becomes fairly watersoluble and is leachedaway from the coated pigment particles by the aqueous phase, oralternatively, it is not eifectively' coated upon the pigment particlein an aqueous system.

Quaternary ammonium compounds useful in accordance with the presentinvention can be represented by the formula curring fats and oils suchas tallow, soybean oil, coconut oil, cottonseed oil, and the like.Examples of lower alkyl radicals coming with the definition of R includemethyl, ethyl and propyl. Specific examples of preferred quaternaryammonium compounds include disoya dimethyl ammonium chloride, dicocodimethyl ammonium chloride, dioctadecyl dimethyl ammonium chloride,dihexadecyl dimethyl ammonium chloride and didodecyl dimet'nyl ammoniumchloride. The first two members of the preceding series are soldcommercially under the trade name Arquad 2S and Arquad 2C.

The tertiary aliphatic amine employed in accordance with the presentinvention can be represented by the formula [CHzOHzOhH i nzcntoi nwherein R is a long chain aliphatic hydrocarbon radical having from 8 to22 carbon atoms and x and y are integers of at least one and having asum not in excess of 10. Examples of aliphatic hydrocarbon radicalscoming within the definition of R include octyl, decyl, dodecyl,tetradecyl, hexadecyl, octadecyl, octadecenyl, octadecadienyl, andoctadecatrienyl radicals. R can also connote statistical mixtures of theforegoing aliphatic hydrocarbon radicals as contained in naturallyoccurring fats and oils such as tallow, soybean oil, coconut oil,cottonseed oil, and the like. Such statistical mixtures of hydrocarbonradicals are named for the natural occurring fats and oils from whichthey are obtained, e.g. soya, coco, etc. Examples of preferred tertiaryaliphatic amines employed in accordance with the present inventioninclude bis(2-hydroxyethyl) soya amine, bis(2-hydroxyethyl) coco amine,bis (Z-hydroxyethyl) oleyl amine, and the like. The first members of thepreceding series are available commercially under the trade namesEthomeen S/ 12 and Ethomeen C/ 12. Also, similar compounds having 5moles and moles of ethylene oxide present therein are availablecommercially under the Ethomeen trade name having a code designation of15, such as S/ 15, C/ 15, and of 20 such as 8/20 and C/20.

Examples of preferred mixtures employed in accordance with the presentinvention include 5 parts by weight of disoya dimethyl ammonium chlorideand 1 part of bis (Z-hydroxyethyl) soya amine, 5 parts by weight ofdisoya dimethyl ammonium chloride and 1 part by weight of his(Z-hydroxyethyl) coco amine, and 5 parts by weight of dicoco dimethylammoniurn chloride and 1 part of his (2-hydroxyethyl) soya amine. i

The present invention includes the use of the abovementioned mixtures ofquaternary ammonium compounds and tertiary aliphatic amines fortreatment of all pigments, including such materials well knowncommercially as iron blue, chrome yellow, chrome orange, chrome green,zinc chromate, calcium carbonate, calcium silicate, Ultramarine,titanium dioxide, black iron oxide, red iron oxide, zinc oxide,lithopone White lead, azo type toners, aluminum hydrate, lakes, carbonblack, zinc sulphide containing pigments, etc. Also within the scope ofour invention are the above pigments as they are ultimately coatedaccording to the process of this invention.

By the term pigment we mean substances which are generally consideredinsoluble in the vehicle as distinguished from dyestuffs which aregenerally considered soluble. For example, pigments generally have theproperty of light 'refractivity, tending to give opacity to the system,whereas dyes generally only have the property of light adsorption,tending to retain the transparency of the system.

The following examples are intended to illustrate the 8 underlyingprinciples of our invention and are not to be construed as undulylimiting:

EXAMPLE I Several precipitated calcium carbonate pigments were coated bythe aqueous slurry method according to the preferred process of thisinvention as hereinabove described. The hydrophilic pigment wasconverted to a hydrophobic pigment by the addition of a Waterdispersible or soluble material that was converted to an oil solubleform by the addition of a second water-soluble material, and a resultingmolecular interchange.

These coated pigments were evaluated in rubber and plastics to determineif they impart any advantages in processing and reinforcing. Powerconsumption, physical properties, aging characteristics etc., were usedto evaluate the effectiveness of the coated pigment.

effectiveness of the coated pigment in rubber.

GR-S formula: Parts (1) GR-S 1502 (polymer) 100.00

(2) Cumar MH #1 (hydrocarbon resin) 20.00 (3) Zinc oxide 5.00 (4)Stearic acid 1.00 (5) Agerite alba (hydroquinone monobenzyl ether) 0.50(6) Altax (benzothiazyl disulfide) 1.50 (7) Thiuram M(tetramethyl-thiuram-disulfide) 0.35 (8) Calcium carbonate pigment125.00 (9) Sulfur 2.50

Total 255.85 Natural rubber formulation:

( 1) Smoked sheet #1 100.00 (2) Zinc oxide 5.00 (3) Stearic acid 1.00(4) P.B.N.A. (phenyl beta n a p h t h y lamine) 0.50 (5) Thiuram M 0.10(6) Altax 1.00 (7 Calcium carbonate pigment 75.00 (8) Sulfur 2.50 (9)Agerite alba (hydroquinone monobenzyl ether) 0.25

Total 185.35

The method'used for evaluating the various filters was the master batchtechnique. All of the ingredients in the on s formulation with theexception of the sulfur and calcium carbonate were master batched. Thenatural rubber formulation was processed in the same manner. It isbelieved this technique eliminates the possibility of error, such asimproved physical properties of one of the compounds, due toprevulcanization during processing. Results are tabulated below:

Table I.Ultra fine particle size CaCO I The following are the recipesused to evaluate the 1 Time required to mill parts of pi ment er 100arts of rubber hydrocarbon in standard recipes. 5 p p Table Il.--Physlcal tests an ultra fine parttcle szze CaCO m the natural rubberformulation Time, Mod. at Tensile, Percent Shore Lbs. Compound Min. F.300%, psi. Elong. l-Iard- Tear 1 p.s.l. ness A 10 287 845 2, 405 540 59No Coating 15 287 820 2, 330 545 57 333 20 287 780 2, 335 540 56 10 2871, 015 2, {150 505 63 0.25% Of Arquad 2CEtho- 15 287 980 2, 545 535 63331 mean 5/12 Acetate. 20 287 940 2, 485 525 61 287 1, 155 2, 295 400 660.5% of Arquad 2C-Etho- 287 1, 105 2, 330 465 08 452 meen 5/12 Acetate.287 1, 045 I 2, 220 465 65 10 287 1, 265 2. 135 425 67 1.0% of Arquad2C-Etho- 15 287 1, 275 2, 375 460 68 337 meet! S112 Acetate. 20 287 1,165 2, 230 450 66 The optimum cure for each of the above compounds weretested for sunlight aging.

The compounds were tested according to ASTM designation: D1l48-S5 for100 hrs. of continual exposure.

In all cases, the compounds containing the calcium carbonate with ourcoating were superior in color to the compounds containing non-coated orfatty acid coated carbonate pigment.

EVALUATION OF POYVER CONSUMPTION Table III.Very fine particle size CaCOI II III IV Type of Coating Arquad Arquad Arquad None 2S-Etlio- ZC-Etho-ZHT-Ethd meen S112 mean 8/12 mean S/12 Acetate Acetate Acetate Amount oiCoating, percent 0.50 0. 50 0. 50 Total Kilowatt Hours 104 1S0 188Percent Power Savings 14. 0 21. 0 17. 5

1 Total kilowatt hours=the amount of power required to disperse thetiller into the standard rubber formulation.

1 Percent Power Savings=tl1e amount of power required to disperse thecoated pigment substractcd from amount of power required to dispurseuncoated pigment gives amount of power saved, this product divided bythe amount of power required to disperse uncoated pigment gives thepercent power saved. 7

The above data indicate power savings are realized with each quaternaryammonium compound employed in the mixture. I

EXAMPLE II The pigments coated in accordance with the procedure ofExample I were evaluated in polyvinylchloride resins. The evaluationconsisted of determining the effect of the coated pigments upon theviscosity of the plastisol and the physical properties of the fusedplastisol film.

The following is the formulation used for the evaluation:

1 Parts Polyvinyl chloride resin (Geon 121). 100.0 Dioctyl phthalate(plasticizer) 65.0 Vanstay S stabilizer 2.5 Vanstay R stabilizer 2.5Calcium carbonate pigment 10.0

Total 180.0

Organic borate, phosphite epoxy complexes. 2 Organic salts of barium andcadmium.

The following plastisols were prepared using the above formulation: 1

Plastisol A B 0 Contains uncoatcd 0.50% coated 1.0% coated CaCOa pig.GaCO; pig. CaCOa pig.

It was found that the coated pigments dispersed into the plastioizer inless time than was required to disperse the uncoated pigments.

The following data is the original viscosity of the three plastisols.This measurement was made 1 hour after the plastisols were deaeratcd.

The viscosities were determined with a Brookfield viscosimeter at F.using a #5 spindle and 20 r.p.m.

Plastisol: Centipoises, F. A 5500-75 B 4800-75 c 4700 7s The threeplastisols were aged at room temperature for a period of two weeks. Atthe end of this aging period, a low shear rheology study was used todetermine the flow characteristics of each of the plastisols.

The following data is the results of the rheology study. A variablespeed Brookfield viscosimeter was used for this study.

All viscosities measured at 75 -F. using a number 5 spindle.

Speed (Rev. per min.) Plastisol A-control 14,000 12,500 10,880 9, S00 9,800 10,000 11, 500 13, 200 13-05% coating 10,200 9.000 7, 760 7,0807,080 7,000 7,800 9, 000 C1.0% coating-.-" 8, 400 7, 500 6, 600 0,1006,100 6, 00 6, 800 7, 800

Viscosity reported in centipoises.

After several weeks of aging the plastisol containing the uncoatedcalcium carbonate was very thick and would not pour from its container,but the other two .plastisols containing the coated pigments were stillfluid.

various concentrations of the combined compounds of this invention andtested for hydrophobicity by a simple water float test; Comparativeresults were obtained with pigment coated only with one of the compoundsof this in- A portion of the plastisols were fused into solid sheetsvention. The results are set forth below: at the end of their two weekaging period. The standard Table I.-Water float test exhibitinghydrophobicity of tensile, modulus, elong., etc., were used to measuretheir 1 lciu arbonate coated pigment physical properties, and sunlightaging, and extraction in haracteristics. Elapsed p test were to determmeag g c Coating Formulation Water ature oi Percent The following are theresults. v Contact Slurry, waited Time 0.

Physical properties 90g??? Arquad 209.10% Ethomecn 7 daysr 30 12Plastisol Modulus Tensile, Percent Hardness Percent 15 Arquad 2C16'66%Ethomeen 30 15 100% Shm'A Mammy 90.90%Arquad2S-9.10% Ethomeen s 12- doso 7 833/471, Arquad 2S-1G.h6% Ethonieen do 30 15 12 Acontrol 415 2v 180415 73 1. 00 BO.5% coating 835 2,0 390 75 1.90 90.90% Arquad S-9.10%Ethomeen 8/12.. lnlitii 30 100 01.0% coating 930 2,105 395 75 1.02

Legend:

Arqiiag 2g =16i-coco liimettllliyll ammonium clllillorige. Arqua 2i-soya iine y ammoniumc ori e. Aging Charactenstws Arquad S=N-soya.triinethyl ammonium chloride.

Ethomeen S/i2=Bis(2-hydroxyethyl) soya amine. Ultra Violet, 200 Percent@Xtractivn, This data indicates that the compounds in combinationcontmmus exmsure 50 exhibit a synergistic effect in that the resultachieved is Plastisol S k E r l greater than the mere total of theindividual eifect's of the 5- 1112808 I11- i. il'iGIB cololw Comm brmmH2O Soap on respectivecompounds. What the exact mechanism of tion tionmerit the potentiating or synergistic effect might be, we are unable toexplain. slight. 0. 37 3.05 5.92 EXAMPLE V do 0. 03 1.09 0. 40 do 0.070. 09 10.34 A simple water float test was performed with a chrome greenpigment treated in an aqueous system with the Arquad ZS-Ethomeen S/ 12combination and compared EXAMPLE III with an uncoated control. Theresults are set forth below: Chrome green, toluidine red, and iron bluepigments Table float tests were coated with the compounds of thisinvention both by the precoating and in situ methods. These pigments C 1Temp. Elapsed Percent oating Additive Percent of Water Pigment alongwith an uncoated control were made into fairly Additive Water ContactWetted high pigmented roller null pastes and passed over a 40 0. Timelaboratory roller mill. A determination was made of grinding time andthe number of passes required to pro- Control 30 lmin- 100 v ute. ducean enamel grind. Table I includes the results of tne Arquad gsEthomenSlum 3 30 7 15 roller mill data obtained.

Table I Chrome Green (Medium Tex- Toluidine Red-Arquad 25- Iron Blue(Milori) (Medium tnre)Arquad ZS-nthomeen Ethomeen 8/12 HardTexture)Arquad 2S- Ethomeen 8/12 Control Coating InSitu Control CoatingIn Situ, Control Coating In Situ Percent Pigment 40 40 40 40 40 40Percfint Vehicle (Varnish Linseed 6 40 40 40 i 0 00 00 60 00 PercentAdditive (Basis Wt. Pig- 60 60 ment) 3 3 3 3 3 3 Grind No. BeforeGrinding 0 1 0 0 2. 5 1.5 0 0 0 1st Eismd T 4 3 H rin ime 5.8 4.8 31.412" 24.3" 10. 2 1'0. 3" 19 Grind No 1. 5 3 2. 5 2. 5 5. 5 5 0 1 a 2ndPass:

Grind Time 5. 7" 0. 2" 5. 3 30. 5" 18. 7" 23. s" 10.0" 1'27" 22. 0"Grind N5 3.5 5 4.5 4.5 0.5 0 2 5.5 4.5 3rd Pass:

Grind T ime 0.5" 6.8 6.2 28.6 14. 7" 22.7" 10.0" 1 20" 27. 7" Grind No 40.5 5 5 7.5 5.5 3 7.5 0.0 Roillgr Cleigange'.)

ront no es 0. 010 0.010 0. 010 0. 010 0.010 0. 010 0.010 0. 010 0.010Back (Inches) 0.015 0.015 0. 015 0.015 0. 015 0. 015 0. 015 0.015 0. 015

N o sweating period allowed for above pigment oil pastes.

Average grind time for three passes of the iron blue paste control aftera 16hour sweating pcri0d=2l8. Grind time on iron blue control representsflow of slightly pigmented base linseed oil with major portion of highlyagglomerated pigment remaining between rolls 2 and 3.

Grind Time:

X'OO =minutes.- OXX =seconds. XXX=minutcs and seconds.

To precoat the pigments Arqiiad -2S and Ethomeeu 8/12 acetate were usedin a 5:1 ratio. For direct addition to the oil paste (in situ) Arquad 2Sand Ethomeen S/12 were used in a'5z1 ratio.

-' EXAMPLE lV Precipitated calcium carbonate pigment were coated byEXAMPLE V1 To show the physical properties of a natural and synthe q Q S'Q 'Y i fhF i D Ve described 7 thet ic rubber formulation containing anultrafine precipi- 1 1 tated CaCO coated pigments were prepared usingthe water slurry method hereinabove described.

All compounding procedures, methods and evaluations were ASTMprocedures. The following were the recipes used for the evaluation or"the pigments.

Natural rubber formulation: Parts Smoked sheet #1 100.00 Zinc oxide 5.00Stearic acid 1.00 10 P.B.N.A. (phenyl-beta-naphthylamine) 0.50 Thiuram M0.10 Altax 1.00 Calcium carbonate pigment 75.00 Sulfur -l 2.50

sunlight aging test used in this evaluation was D620-49 with acontinuous exposure for 200 hours. In each case, the rubbers with thecoated calcium carbonates appeared superior in this color test to thosecompounds containing the non-coated calcium carbonates.

T able I.-Physical properties of compounded rubbers Pigment CoatingModulus, Percent Sunli ht Type Rubber Size, On Cure Temp, p.s.i. atTensile, Elonga- Shore Lbs. Aging Dis- Microns Pigment Time F. 300%p.s.i. tion Hardness Tear coloration Ultimate 0. 036-0. 040 None 10 287845 2, 405 540 59 335 Good. 0. 036-0. 040 None 15 287 820 2, 330 545 67300 Do. 0. 036-0. 040 N one 20 2 780 2, 235 540 56 285 Do. 0. 036-0. 04010 287 1, 015 2, 450 505 03 360 Very Good. 0. 036-0. 040 15 287 980 2,5-15 535 63 330 Do. i 0. 036-0. 040 20 287 940 2, 485 525 61 310 D0. 10036-0040 287 1,155 2, 295 460 66 400 Do. 0. 036-0. 040 287 1, 105 2,330 405 68 450 D0. 0. 036-0. 040 287 1, 045 2, 220 465 365 Do. 0. 036-0.040 10' 287 1, 265 2, 135 425 67 330 D0. 0. 036-0. 040 15 287 1, 275 2,375 460 68 340 Do. 0. 036-0. 040 287 1, 2, 230 450 66 340 D0.

1 0.25% of a 83.34% Arquad 2C-16.66% Ethomeen S/12 blend. 3 0.5% of a83.31% Arquad 2C-16.66% Etliomeen S112 blend. 3 1.0% of a 83.34% Arquad2016.667}, Ethomeen S/12 blend.

,Table II.-Physz-cal properties of compounded rubbers Pigment CoatingModulus, Percent Sunlight Type Recipe Size, On Cure Temp, p.s.i. atTensile, Elonga- Shore Lbs. Aging Dis- Microns Pigment Time F. 300% psi.tien Hardness Tear coloration Ultimate 036-. 040 None 7% 307 260 1, 400660 54 245 Good. .036.040 None 10 307 320 1,715 565 57 270 D0. .036-.040 None 15 307 1 375 1, 520 540 58 200 D0. 036-. 040 7 6 307 700 1, 230360 66 165 Very Good. 036-. 040 10 307 815 1,185 335 67 210 Do. 036-.040 15 307 V 780 1, 3 10 66 190 Do. .036-. 040 7%" 307 635 1, 215 410 65210 Do. 1136-. 040 10 307 685 1, 160 355 66 190 D0. 036-. 040 15 307 7251, 340 66 D0.

0.25% of a 83.34%

9 Contains only 3-5 of antioxidant shown in recipe.

Antioxidant (hydroqninone mono-henzyl Arquad 2C-16.66% Ethomeen 8/12Acetate blend.

EXAMPLE VII To demonstrate that improvements in pigment dispersion arealso possible by the in situ coating of calcium carbonate in the rubbermatrix, a 5:1 blend of Arquad 2C and Ethomeen 5/12 was added to therubber matrix in a rubber mill, just before the addition of the pigment.Table I shows the improvement in physical properties with in situcoating.

Table I.In situ addition of cationic chemicals Cure Cure 300% Tensile,Percent Shore Lbs. Ultra Fine Pigment Rubber Time, Temp., Modulus p.s.i.Elong. Hard- Tear Minutes F. ness A 10 7 845 2, 405 540 59 3350%galgeaticle Sise N on- Natural. 15 287 820 2,330 545 57 300 20 287 7802, 235 540 56 285 Precnated Pigment, 1% do 10 287 1,265 2,135 425 67 330of Arquad 2C-Etho- 15 287 1, 275 2,375 460 68 340 mean 3/12 Acetate. 20287 1,165 2, 230 450 66 340 In' Situ Coating, 1% of do 10 287 1,3302,380 435 66 300 of Arquad 2C-Etho- 15 287 1,320 2, 475 460 68 320 meen8/12. 20 287 1, 250 2, 120 425 67 320 13 SRF (semi reinforcing furnace)carbon black pigment was coated with 1% of the Arquad ZC-Ethomeen S/12acetate in a :1 ratio in accordance with the aqueous slurry methodhereinabove described. The dried pigment was evaluated against anequivalent amount of uncoated pigment to determine the incorporationtime required to disperse the pigment into the rubber formulations givenin Example I. The coated pigment dispersed into the rubber formulationsin 25% less time than required to disperse the uncoated pigment.

EXAMPLE IX SRF carbon black pigment was coated as described in ExampleVIII. The coated pigment and an uncoated pigment were incorporated intoPVC (polyvinyl chloride) plastisol having the following formulation:

Parts PVC resin (polyvinyl chloride) 88.20 DOP (dioctyl phthalate) 57.45Vanstay S and R (heat and light stabilizer) 4.35 SRF carbon black 1.00

Total 151.00

The advantages of the formulation containing the coated pigment were asfollows:

(1) Improved dispersion of the carbon black.

(2) Greater viscosity stability than the control.

(3) Improved anti-static properties of the fused plastisol film.

EXAMPLE X Employing the GRS formulation set out in Example I, carbonblack pigment coated with the combination of Arquad ZC-Ethomeen S/ 12acetate in 5:1 ratio was compared with a control and the formulationcontaining car 1 The .5% refers to the weight of coating on the pigment.

Although this invention has been described and exemplified in terms ofits preferred embodiments, those skilled in the art will appreciate thatmany changes can be made without departing from the spirit and scope ofthe invention.

We claim:

1. A pigment particle uniformly coated with from 0.05 to 5 weightpercent based on the weight of dry pigment of a mixture consistingessentially of from 0.25 to parts of a quaternary ammonium compoundhaving the formula X R R per part of a tertiary aliphatic amine havingthe formula l'CHzCHaOhH RCH CH OLVH wherein in each of the foregoingformulae R is an aliphatic hydrocarbon radical having from 8 to 22carbon atoms, R is a lower alkyl radical having from 1 to 3 carbonatoms, X is a halogen selected from the group the formula R OH,

\N/ 01 R/ om per part of a tertiary aliphatic amine having the formulaCHZCHZOH \CH2CH2OH wherein R in each of the foregoing formulae is analiphatic hydrocarbon radical having from 8 to 22 carbon atoms.

3. A pigment particle uniformly coated with from .05 to 5 weight percentbased on the Weight of dry pigment of a mixture consisting essentiallyof from 5 to 10 parts by weight of disoya dirnethyl ammonium chlorideper part of bis(2 -hydroxyethyl) soya amine.

4. A pigment particle uniformly coated with from 0.05 to 5 weightpercent based on the weight of dry pigment of a mixture consistingessentially of from 5 to 10 parts by weight of dicoco dimethyl ammoniumchloride per part of bis(2-hydroxyethyl) soya amine.

5. A calcium carbonate pigment particle uniformly coated With from 0.05to 1.0 weight percent based on the weight of dry pigment of a mixtureconsisting essentially of from 5 to 10 parts by Weight of a quaternaryammonium compound having the formula per part of a tertiary aliphaticamine having the formula CHzCHrOLH wherein in each of the foregoingformulae R is an aliphatic hydrocarbon radical having from 8 to 22carbon atoms, R is a lower alkyl radical having from 1 to 3 carbonatoms, X is a halogen selected from the group consisting of chlorine andbromine, and x and y are integers of at least 1 and having a sum of from2 to 10.

6. A calcuim carbonate pigment according to claim 5 uniformly coatedwith a mixture consisting of 5 parts of disoya dimethyl ammoniumchloride per part of bis(2- hydroxyethyl) soya amine.

7. An iron blue pigment coated according to claim 1.

8. A chrome green pigment coated according to claim 1.

9. A toluidine red pigment according to claim 1.

10. A process comprising adding with agitation to an aqueous pigmentsystem from 0.05 to 5 weight percent based on the amount of dry pigmentof a mixture consisting' essentially of from 5 to 10 parts by weight ofa quaternary ammonium compound having the formula per part of awater-soluble salt of a tertiary aliphatic amine having the formula)OH2CH2O1XH iomoniopn wherein in each of the formulae R is analiphatichydrocarbon radical having from 8 to 22 carbon atoms, R' is a loweralkyl radical having from 1 to 3 carbon atoms, X is a halogen selectedfrom the group consisting of chlorine and bromine, and x and y areintegers of at least 1 and having a sum of from 2 to 10; adding withagitation to the aqueous mixture an equivalent amount of a dilutesolution of an alkali metal hydroxide to convert the tertiary aliphaticamine salt on the pigment particle to the tertiary aliphatic amine andto dissolve the resulting alkali metal salt reaction product in theaqueous phase; and separating the thus coated pigment from the aqueousphase.

11. A process comprising adding with agitation to an aqueous pigmentsystem from 0.05 to 5 weight percent based on the amount of dry pigmentof a mixture consisting essentially of from 5 to parts by weight of aquaternary ammonium compound having the formula R om \N/ 01 R/ \CH2 perpart of a water-soluble salt of a tertiary aliphatic amine having theformula wherein in each of the formulae R is an aliphatic hydrocarbonradical having from 8 to 22 carbon atoms; adding With agitation to theaqueous mixture an equivalent amount of a 1% sodium hydroxide solutionto convert the tertiary aliphatic amine salt on the pigment particle tothe tertiary aliphatic amine and to dissolve the resulting sodium saltproduct in the aqueous phase; and separating the thus coated pigmentfromthe aqueous phase.

12. A process comprising adding with agitation to an aqueous pigmentsystem from 0.05 to 5 weight percent based on the amount of dry pigmentof a mixture con sisting essentialTy of 5 parts by weight of disoyadimethyl ammonium chloride per part of the acetate salt of bis(2-hydroxyethyl) soya amine; adding with agitation to the aqueous mixturean equivalent amount of a 1% aqueous solution of sodium hydroxide toconvert the acetate salt on the pigment particle to the tertiaryaliphatic amine and to dissolve the resulting sodium acetate in theaqueous phase; and separating the thus coated pigment from the aqueousphase.

13. A process comprising adding with agitation to an aqueous pigmentsystem from .05 to 5 weight percent based on the amount of dry pigmentof a mixture consisting essentially of 5 parts by Weight of dicocodimethyl ammonium chloride per part of the acetate salt of bis(2-hydroxyethyl) soya amine; adding with agitation to the aqueous mixturean equivalent amount of a 1% aqueous solution of sodium hydroxide toconvert the acetate salt on the pigment particle to the tertiaryaliphatic amine and to dissolve the resulting sodium acetate in theaqueous phase; and separating the thus coated pigment from the aqueousphase.

14. A process comprising adding with agitation to an aqueous pigmentsystem from .05 to 5 Weight percent based on the amount of dry pigmentof a mixture consisting essentially of 5 parts by Weight of dicocodimethyl ammonium chloride per part of the acetate salts of bis(2-hydroxyethyl) coco amine; adding with agitation to the aqueous mixturean equivalent amount of a 1% aqueous solution sodium hydroxide toconvert the acetate salt on the pigment particle to the tertiaryaliphatic amine and to dissolve the resulting sodium acetate in theaqueous phase; and separating the thus coated pigment from the aqueousphase.

15. A process comprising adding to a substantially nonaqueous pigmentvehicle from about 0.05 to about 5 weight percent based on the amount ofdry pigment to be added of a mixture consisting essentially of fromabout 5 to about 10 parts by weight of a quaternary ammonium compoundhaving the formula per part of a soluble tertiary aliphatic amine havingthe formula wherein in each of the formulae R is an aliphatichydrocarbon radical having from 8 to 22 carbon atoms, R is a lower alkylradical having from 1 to 3 carbon atoms, X is a halogen selected fromthe group consisting of chlorine and bromine, and x and y are integersof at least 1 and having a sum of from 2 to 10; and adding pigment tothe said vehicle.

16. A process comprising adding to a substantially non-aqueous pigmentvehicle from about 0.05 to about 5 weight percent based on the amount ofdry pigment to be added of a mixture consisting essentially of from 5 to10 parts by weight of a quaternary ammonium compound having the formulaer part of a soluble tertiary aliphatic amine having the formula whereinin each of the formulae R is an aliphatic hydrocarbon radical havingfrom S to 22 carbon atoms; and adding pigment to the said vehicle.

17. A process comprising adding to a substantially non-aqueous pigmentvehicle from about 0.05 to about 5 weight percent based on the amount ofdry pigment to be added of a mixture consisting essentially of 5 partsby weight of disoya dimethyl ammonium chloride per part ofbis(2-hydroxyethyl) soya amine; and adding pigment to the said vehicle.

18. A process comprising adding to a substantially non-aqueous pigmentvehicle from about 0.05 to about 5 weight percent based on the amount ofdry pigment to be added of a mixture consisting essentially of 5 partsby weight of dicoco dimethyl ammonium chloride per part orbisQ-hydroiryethyl) coco amine; and adding pigment to the said vehicle.

References Cited in the file of this patent UNITED STATES PATENTS2,192,956 Sloan er al. Mar. 12, 1940 2,572,217 Thurmond Oct. 23, 19512,674,619 Lundsted Oct. 19, 1953 2,681,314 Skinner et al. June 15, 19542,754,219 Voet et al. July 10, 1956 2,819,210 Haden et al. Jan. 7, 19582,841,504 Liggett i July 1, 1958 OTHER REFERENCES Fischer et al.:Industrial and Engineering Chemistry,

No. March 1943, pages 336-342..

1. A PIGMENT PARTICLE UNIFORMLY COATED WITH FROM 0.05 TO 5 WEIGHTPERCENT BASED ON THE WEIGHT OF DRY PIGMENT OF A MIXTURE CONSISTINGESSENTIALLY OF FROM 0.25 TO 10 PARTS OF A QUATERNARY AMMONIUM COMPOUNDHAVING THE FORMULA